Methods for quantitating the efficacy of oral care products (e.g., toothpaste, mouthwash etc.) at dislodging cells from biofilm test surfaces or inhibiting or delaying the accumulation of cells on a test surface have generally been described. Also, fluorescent probes, and confocal laser scanning microscopy (CLSM), have been generally used to assess bacterial vitality of biofilm. Stannous (Sn2+) has been added to oral care products to prevent dental plaque and oral disease. Sn2+ is found to effectively inhibit certain bacteria that can lead to tooth decay in human interproximal dental plaque. However, there is a need for a specific method at quantitating the efficiency of stannous containing oral care products, and its bacteriostatic or bactericidal efficacy against biofilm.